ADD: cmd_voxeldownsample

docs/cmd_description/Cockroach_ClusterColor.md

@@ -13,7 +13,7 @@ parent: Cmd Description
 
 This is a clustering technique based on color. It will cluster the pointcloud based on the color of the points . It is often useful to cluster a pointcloud based on color to separate different colored component of a pointcloud. Note that this command can be used also with *grayscale* colors as in the image. As many clustering techniques the command uses a [KNNsearch](https://en.wikipedia.org/wiki/K-nearest_neighbors_algorithm) to find the colors relations of neighbors of each point.
 
-The main algorithm is based on the *Connected Component Extractor* with a color proximity evaluator from the function in [cilantro::ConnectedComponentExtraction3f](https://github.com/kzampog/cilantro/blob/57ad1a397b73b6f4bbf9604fd75f8fe4363206a7/include/cilantro/clustering/connected_component_extraction.hpp#L23).
+The main algorithm is based on the *Connected Component Extractor* with a color proximity evaluator from the function in [cilantro::ConnectedComponentExtraction3f()](https://github.com/kzampog/cilantro/blob/57ad1a397b73b6f4bbf9604fd75f8fe4363206a7/include/cilantro/clustering/connected_component_extraction.hpp#L23).
 
 **Command options:**
 ```

docs/cmd_description/Cockroach_VoxelDownsample.md

@@ -0,0 +1,21 @@
+---
+layout: default
+title: Cockroach_VoxelDownsample
+parent: Cmd Description
+---
+
+# `Cockroach_VoxelDownsample`
+{: .no_toc }
+
+![img_downsample](https://github.com/ibois-epfl/Cockroach-documentation/blob/docu-alpha/img/cmds/cockroach_voxeldownsample.jpg?raw=true)
+
+Downsaample a pointcloud based on a grid with a given distance (a voxel grid). If two or more points are in the same voxel, only one point will be kept. This is a very fast way to downsample a pointcloud. The command will output a pointcloud that is the result of the downsampling. The result will have a regular appearance.
+
+The main algorithm is based on the the function in [open3d::geometry::VoxelDownSample()](http://www.open3d.org/docs/0.7.0/cpp_api/_down_sample_8cpp.html).
+
+**Command options:**
+```
+VoxelSize=0.01
+```
+{: .fs-6 .fw-300 }
+This is the size of the voxel. The smaller the value, the more points will be removed.